Professional cameras, such as for example photo cameras, film cameras or video cameras, are employed out in the open under the most varied of weather conditions. Resulting here is the problem that raindrops, snow, dust particles, etc., precipitate on the outer lens of the objective. Arising from this are lack of definition and distortions when taking pictures, the quality of the photo, as a whole, being impaired and the user is continually busy keeping the precipitates from the lens and/or cleaning the lens.